CO2 Waterless Fracturing and Huff and Puff in Tight Oil Reservoir

2021 ◽  
Author(s):  
Weixiang Cui ◽  
Li Chen ◽  
Chunpeng Wang ◽  
Xiwen Zhang ◽  
Chao Wang
Keyword(s):  
Energy Storage ◽  
Oil Recovery ◽  
Low Permeability ◽  
Oil Viscosity ◽  
Integrated Development ◽  
Oil Displacement ◽  
Reservoir Volume ◽  
Water Based ◽  
Development Technology ◽  
Tight Reservoirs

Abstract CO2 fracturing technique is a kind of ideal waterless stimulation tech. It has the advantages of water free, low reservoir damage, and production increase by improving the reservoir pressure. At the same time, combined with reasonable shut-in control after fracturing, it can be realized integrated development technology of energy storage -fracturing and oil displacement with CO2 waterless stimulation. For low-grade and low-permeability tight reservoirs, through the integration technology of CO2 fracturing and CO2 flooding, fracture-type "artificial permeability" is formed in the formation, and micro-nano pore throat of underground matrix is formed as oil and gas production system, which realizes the development of artificial energy, reduces carbon emissions, effectively improves the productivity of low-permeability and tight reservoirs, thus further improves oil recovery. The technology mainly includes two aspects: vertical wells adopt CO2 fracturing + huff and puff displacement integration technology, horizontal wells adopt water-based fracturing + CO2 displacement technology, and utilize the high efficiency of CO2 penetration in reservoirs and crude oil viscosity reduction, which can greatly improve oil recovery, while achieving large-scale CO2 storage and reducing carbon emissions. It is both realistic and economic, and has great social benefits. The integrated development technology of energy storage -fracturing and oil displacement with CO2 waterless stimulation has been applied for 10 wells in oilfield, which has achieved good results in increasing reservoir volume, increasing formation energy, reducing oil viscosity and enhancing post-pressure recovery. As a result, the production of them has increased by over 100%. With low viscosity and high diffusion coefficient, supercritical CO2 is good for improving fracturing volume. Effective CO2 fracturing technology can improve stimulated reservoir volume, downhole monitoring results show that the cracks formed by CO2 fracturing is 3 times the size of those formed by water-based fracturing.

scholarly journals Influence of Oil Viscosity on Alkaline Flooding for Enhanced Heavy Oil Recovery

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yong Du ◽  
Guicai Zhang ◽  
Jijiang Ge ◽  
Guanghui Li ◽  
Anzhou Feng
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
High Viscosity ◽  
Low Permeability ◽  
Oil Viscosity ◽  
Low Viscosity ◽  
Medium Permeability ◽  
Tertiary Oil Recovery ◽  
Different Temperatures ◽  
Water Drops

Oil viscosity was studied as an important factor for alkaline flooding based on the mechanism of “water drops” flow. Alkaline flooding for two oil samples with different viscosities but similar acid numbers was compared. Besides, series flooding tests for the same oil sample were conducted at different temperatures and permeabilities. The results of flooding tests indicated that a high tertiary oil recovery could be achieved only in the low-permeability (approximately 500 mD) sandpacks for the low-viscosity heavy oil (Zhuangxi, 390 mPa·s); however, the high-viscosity heavy oil (Chenzhuang, 3450 mPa·s) performed well in both the low- and medium-permeability (approximately 1000 mD) sandpacks. In addition, the results of flooding tests for the same oil at different temperatures also indicated that the oil viscosity put a similar effect on alkaline flooding. Therefore, oil with a high-viscosity is favorable for alkaline flooding. The microscopic flooding test indicated that the water drops produced during alkaline flooding for oils with different viscosities differed significantly in their sizes, which might influence the flow behaviors and therefore the sweep efficiencies of alkaline fluids. This study provides an evidence for the feasibility of the development of high-viscosity heavy oil using alkaline flooding.

The Development Technology Policy of Secondary Oil Recovery in the Overpressure Carbonate Reservoir

2013 ◽  
Vol 680 ◽  
pp. 295-300
Author(s):  
Ye Fei Chen ◽  
Zi Fei Fan ◽  
Jun Ni ◽  
Yun Juan Li ◽  
Qing Ying Hou
Keyword(s):  
Oil Recovery ◽  
Technology Policy ◽  
Water Injection ◽  
Carbonate Reservoir ◽  
Low Permeability ◽  
Development Mode ◽  
Engineering Research ◽  
Well Spacing ◽  
Development Technology ◽  
Secondary Oil Recovery

Kenkiyak oilfield in kazakstan is a low porosity, extremely low permeability and overpressure carbonate reservoir. There are different reservoir and fracture characteristics in different region. The formation pressure decline seriously and water cannot be injected into the low permeability zone. Referring to the domestic and oversea research achievement, integrating regional geologic characteristics, numerical simulation results and reservoir engineering research results, we optimize a series of the development technology policy, including the reasonable gas and water injection modes and injection opportunity, the suitable well patterns and well spacing. Meanwhile, the development mode of energy supplement in the extremely low permeability and overpressure reservoir is explored.

scholarly journals Improving Oil Recovery of the Heterogeneous Low Permeability Reservoirs by Combination of Polymer Hydrolysis Polyacrylamide and Two Highly Biosurfactant-Producing Bacteria

2021 ◽  
Vol 14 (1) ◽  
pp. 423
Author(s):  
Shuwen Xue ◽  
Yanhong Zhao ◽  
Chunling Zhou ◽  
Guangming Zhang ◽  
Fulin Chen ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Low Permeability ◽  
Bacterial Fermentation ◽  
The Core ◽  
Oil Displacement ◽  
Polymer Hydrolysis ◽  
Enhance Oil Recovery ◽  
Low Permeability Reservoirs ◽  
Microbial Flooding ◽  
Poly Acrylamide

Polymer hydrolysis polyacrylamide and microbes have been used to enhance oil recovery in many oil reservoirs. However, the application of this two-method combination was less investigated, especially in low permeability reservoirs. In this work, two bacteria, a rhamnolipid-producing Pseudomonas aeruginosa 8D and a lipopeptide-producing Bacillus subtilis S4, were used together with hydrolysis poly-acrylamide in a low permeability heterogeneous core physical model. The results showed that when the two bacterial fermentation liquids were used at a ratio by volumeof 1:3 (v:v), the mixture showed the optimal physicochemical properties for oil-displacement. In addition, the mixture was stable under the conditions of various temperature (20–70 °C) and salinity (0–22%). When the polymer and bacteria were mixed together, it had no significant effects in the viscosity of polymer hydrolysis polyacrylamide and the viability of bacteria. The core oil-displacement test displayed that polymer hydrolysis polyacrylamide addition followed by the bacterial mixture injection could significantly enhance oil recovery. The recovery rate was increased by 15.01% and 10.03%, respectively, compared with the sole polymer hydrolysis polyacrylamide flooding and microbial flooding. Taken together, these results suggest that the strategy of polymer hydrolysis poly-acrylamide addition followed by microbial flooding is beneficial for improving oil recovery in heterogeneous low permeability reservoirs.

scholarly journals Ultra-Low Interfacial Tension Foam System for Enhanced Oil Recovery

2019 ◽  
Vol 9 (10) ◽  
pp. 2155 ◽  
Author(s):  
Qi Liu ◽  
Shuangxing Liu ◽  
Dan Luo ◽  
Bo Peng
Keyword(s):  
Liquid Phase ◽  
Interfacial Tension ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Foaming Properties ◽  
Oil Viscosity ◽  
Important Indicator ◽  
Oil Displacement ◽  
Displacement Capacity ◽  
Foam Flooding

The liquid phase of foam systems plays a major role in improving the fluidity of oil, by reducing oil viscosity and stripping oil from rock surfaces during foam-flooding processes. Improving the oil displacement capacity of the foam’s liquid phase could lead to significant improvement in foam-flooding effects. Oil-liquid interfacial tension (IFT) is an important indicator of the oil displacement capacity of a liquid. In this study, several surfactants were used as foaming agents, and polymers were used as foam stabilizers. Foaming was induced using a Waring blender stirring method. Foam with an oil-liquid IFT of less than 10–3 mN/m was prepared after a series of adjustments to the liquid composition. This study verified the possibility of a foam system with both an ultra-low oil-liquid IFT and high foaming properties. Our results provide insight into a means of optimizing foam fluids for enhanced oil recovery.

Study on In Situ Carbon Dioxide-Generation Flooding

2012 ◽  
Vol 502 ◽  
pp. 179-183
Author(s):  
Hong Jing Zhang ◽  
Shuang Bo Dong ◽  
Zhe Kui Zheng
Keyword(s):  
Carbon Dioxide ◽  
Oil Recovery ◽  
Flow Direction ◽  
Physical Models ◽  
Viscosity Reduction ◽  
Oil Viscosity ◽  
Foamy Oil ◽  
Oil Displacement ◽  
Generation Technology

Aiming at the source and corrosiveness of carbon dioxide, the in-situ carbon dioxide generation technology to enhance oil recovery was proposed。This paper presents the in-situ carbon dioxide generation technology mechanism, the expansion, viscosity reduction; oil-displacement efficiency and foamy oil of this technology were experimentally evaluated by using microscopic models and physical models. The experimental results indicated that the in-situ carbon dioxide generation technology could be used to produce enough carbon dioxide and get good efficiencies of oil expansion, reduction of viscosity and enhancement of oil displacement. Under the conditions of 2010mPa•s in oil viscosity, 60°C and 10MPa, the volume of oil could be expanded by25%, and the viscosity of oil can reduced to 52.7% , and the CO2 can displacement，restraining viscous fingering and changing liquid flow direction and carrying the residual oil.

Characteristics and Influence Factors for Oil Displacement Efficiency by the Micro-Model Water Flooding Experiment in Low Permeability Reservoir

2015 ◽  
Vol 1092-1093 ◽  
pp. 1371-1374
Author(s):  
Xiang Chun Zhang ◽  
Wei Sun ◽  
Tian Li Rao ◽  
Hai Zeng Jing ◽  
Yong Jing ◽  
...  
Keyword(s):  
Influencing Factors ◽  
Influence Factors ◽  
Water Flooding ◽  
Low Permeability ◽  
Micro Model ◽  
Displacement Efficiency ◽  
Oil Viscosity ◽  
Oil Displacement ◽  
Piston Displacement ◽  
Oil Displacement Efficiency

Through the displacement experiment of low permeability sandstone micro model of water Erdos basin, summing up the water displacing oil characteristics, and to explore the influencing factors of micro water oil displacement efficiency. The study found that, the water flooding characteristic main performance for: flooding mode mainly by non piston displacement; heterogeneity is strong, the oil displacement efficiency is low; the crude oil viscosity is low, the oil displacement efficiency is high; the main influencing factors are: physical; heterogeneity; displacement ratio. Therefore, for low permeability sandstone reservoir development, process parameters should be selected reasonably, in order to ensure the good development effect.

scholarly journals Development and Application of Efficient Oil Displacement System for Middle-Low Permeability and High Pour-Point Heavy Oil Reservoirs

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhenfu Ma ◽  
Kai Zhang ◽  
Mengjie Zhao ◽  
Lu Liu ◽  
Chao Zhong ◽  
...  
Keyword(s):  
Crude Oil ◽  
Pour Point ◽  
Freezing Point ◽  
Reduction Rate ◽  
Field Application ◽  
Viscosity Reduction ◽  
Low Permeability ◽  
Oil Viscosity ◽  
Oil Displacement ◽  
Displacement System

In view of the problems of low permeability, high oil viscosity and freezing point, and low productivity of single well in Luo 321 and Luo 36 blocks of Luojia Oilfield, the chemical viscosity-reducing cold production technology was studied. By analyzing the properties of crude oil, it is concluded that the reason for high viscosity and high freezing point is the high content of asphaltene, pectin, and wax. The viscosity is mainly affected by asphaltene; the wax precipitation point and pour point are mainly affected by the wax; and the solidification point is affected by the wax and asphaltene. The treatment idea of reducing viscosity and inhibiting wax is determined. By compounding the synthetic pour point depressant POA-VA and the viscosity reducer DBD-DOPAMA, the effect of reducing the viscosity and freezing point of crude oil was evaluated. PD-7 (POA-VA 40%, DBD-DOPAMA 50%, and P-10C 10%) system was selected as the optimal formula. When the concentration of the system is 10%, the viscosity reduction rate reaches 95.2%; the freezing point can reduce by 10.2°C; it has good oil sample adaptability, salinity resistance, and temperature resistance; and the oil washing rate can reach more than 60%. The oil displacement system was injected into the formation by means of multiconcentration and multislug and was applied in the field of Luo 321-2 Well. A total of 500 t of the oil displacement system was injected, and the effect of measures lasted for 400 days, with a cumulative oil increase of 883 t. It has been applied in different blocks 30 times and achieved a good field application effect.

Three-Dimensional Visualization of Oil Displacement by Foam in Porous Media

2021 ◽  
Author(s):  
Josiah Siew Kai Wong ◽  
Tetsuya Suekane
Keyword(s):  
Porous Media ◽  
Oil Recovery ◽  
Three Dimensional ◽  
The Other ◽  
Oil Viscosity ◽  
Fluid Displacement ◽  
Oil Displacement ◽  
Gas Flooding ◽  
Displacement Patterns ◽  
Foam In Porous Media

Abstract Foam Enhanced Oil Recovery (EOR) has been employed as an improved recovery method due to its best sweep efficiency and best mobility control over the other injection method such as gas flooding, water flooding and other EOR methods. Foam which has high viscosity illustrates great potential for displacing liquid. The relative immobility of foam in porous media seems to be able to suppress the formation of fingers during oil displacement leading a more stable displacement. However, there are still various parameters that may influence the efficiency of foam assisted oil displacement such as oil properties, permeability of reservoir rock, physical and chemical properties of foam, and other parameters. Also, the interaction and displacement patterns of foam inside the porous media are remained unknown. Thus, in this study, we investigated the three-dimensional (3D) characteristics of oil recovery with gases, water, surfactant, and foam injection in a porous media set-up. By using CT scanning machine, the fluid displacement patterns were captured and analyzed. Moreover, the effect of oil viscosity on foam displacement patterns is studied. The study provides a qualitative and quantitative experimental visualization of 3D displacement structure, oil recovery with gases, liquid and foam injection. As a result, the comparison of fluid displacement patterns between gases, water, surfactant and foam injection show that foam has the good ability in sweeping and forms stable displacement front. The combination of surfactant, liquid and gas, which makes up foam resulted in a synergistic effect in oil displacement. On the other hand, viscous fingering, gravity segregation, trapped oil phenomena are shown in gas flooding and liquid flooding experiments. Thus, foam which displaced stably across the permeable bed resulted in the highest oil recovery factor. The mechanism of foam flow in porous media was understood in this study. Foam, as a series of bubble, burst and become free moving liquid and gas particles when in contact with oil and porous media. Therefore, two displacement fronts could be found from the foam injection experiment, in which the front layer moving ahead in contacting with oil bank is the discontinuous gas/liquid layer and followed by stably foam bank at the back. Due to the stable displacement of foam bank, the effect of oil viscosity on foam displacement is suppressed and showed no distinction in terms of displacement patterns. The flow regimes are found to be the same despite different viscosity of displaced oil. There has been no linear correlation proved between the oil viscosity and oil recovery factor.

scholarly journals Review on enhanced oil recovery by nanofluids

2018 ◽  
Vol 73 ◽  
pp. 37 ◽  
Author(s):  
Kewen Li ◽  
Dan Wang ◽  
Shanshan Jiang
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Surface Tension ◽  
Oil Recovery ◽  
Wettability Alteration ◽  
Oil Viscosity ◽  
Interfacial Surface ◽  
Lack Of Control ◽  
Water Based ◽  
Enhance Oil Recovery

The addition of nanoparticles into water based fluids (nanofluid) with or without other chemicals to Enhance Oil Recovery (EOR) has recently received intensive interest. Many papers have been published in this area and several EOR mechanisms have been proposed. The main EOR mechanisms include wettability alteration, reduction in InterFacial surface Tension (IFT), increase in the viscosity of aqueous solution, decrease in oil viscosity, and log-jamming. Some of these mechanisms may be associated with the change in disjoining pressure because of the addition of the nanoparticles. The experimental data and results reported by different researchers, however, are not all consistent and some even conflict with others. Many papers published in recent years have been reviewed and the associated experimental data have been analyzed in this paper in order to clarify the mechanisms of EOR by nanofluids. Wettability alteration may be one of the most accepted mechanisms for nanofluid EOR while reduction in IFT and other mechanisms have not been fully proven. The main reason for the inconsistency among the experimental data might be lack of control experiments in which the effect of nanoparticles on oil recovery would be singled out.

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